Showing papers by "University of Coimbra published in 2004"
TL;DR: While the incorporation of PEG-lipids reduces the pH-dependent release of encapsulated fluorescent markers in vitro, it does not hinder the cytoplasmic delivery of the markers per cell-associated liposome, suggesting that intracellular delivery is not dictated simply by the destabilization of the liposomes.
481 citations
TL;DR: In this article, a study of community trade marks (CTM), an intellectual property right granted in the European Union, and drawing on recent research on trademarking trends in Portugal, is presented.
400 citations
TL;DR: In this article, a sufficiently varied source of experimental data already exists to show that hornification is only a particular case of lactone bridge formation in lignocellulosic materials.
Abstract: Although perfectly diagnosed in terms of the occurrence of physical changes, the hornification phenomenon, in its origin, has frequently been associated with the formation of irreversible or partially reversible hydrogen bonding in wood pulps or paper upon drying or water removal. Its characterisation has therefore been confusing and unsatisfactory. The authors propose that a sufficiently varied source of experimental data already exists to show that hornification is only a particular case of lactone bridge formation in lignocellulosic materials.
374 citations
TL;DR: This review will focus on the events that characterize apoptotic death in PDT and on the intracellular signaling events that are set in motion in photosensitized cells.
371 citations
TL;DR: The potent antifungal activity of the essential oils of Thymus on Candida spp.
Abstract: The increasing recognition and importance of fungal infections, the difficulties encountered in their treatment and the increase in resistance to antifungals have stimulated the search for therapeutic alternatives. Essential oils have been used empirically. The essential oils of Thymus (Thymus vulgaris, T. zygis subspecies zygis and T. mastichina subspecies mastichina) have often been used in folk medicine. The aim of the present study was to evaluate objectively the antifungal activity of Thymus oils according to classical bacteriological methodologies - determination of the minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) - as well as flow cytometric evaluation. The effect of essential oils upon germ tube formation, an important virulence factor, was also studied. The mechanism of action was studied by flow cytometry, after staining with propidium iodide. The chemical composition of the essential oils was investigated by gas chromatography (GC) and gas chromatography/mass spectroscopy (GC/MS). The antifungal activity of the major components (carvacrol, thymol, p-cymene and 1,8-cineole) and also possible interactions between them were also investigated. The essential oils of T. vulgaris and T. zygis showed similar antifungal activity, which was greater than T. mastichina. MIC and MLC values were similar for all the compounds tested. At MIC values of the essential oils, propidium iodide rapidly penetrated the majority of the yeast cells, indicating that the fungicidal effect resulted primarily from an extensive lesion of the cell membrane. Concentrations below the MIC values significantly inhibited germ tube formation. This study describes the potent antifungal activity of the essential oils of Thymus on Candida spp., warranting future therapeutical trials on mucocutaneous candidosis.
363 citations
TL;DR: In this paper, the authors focus on very simple methodologies that permit one to calculate accurately the mixture's molar volumes and heat capacities as well as more sophisticated theories to predict excess properties, pressure and isotope effects in the phase diagrams, and anomalies in some response functions to criticality, with a minimum of information.
327 citations
TL;DR: In this article, the authors investigated the growing time scales and oscillation frequencies as a function of the mirror's location and showed that in order for the system black hole plus mirror to become unstable there is a minimum distance at which the mirror must be located.
Abstract: A wave impinging on a Kerr black hole can be amplified as it scatters off the hole if certain conditions are satisfied, giving rise to superradiant scattering. By placing a mirror around the black hole one can make the system unstable. This is the black-hole bomb of Press and Teukolsky. We investigate in detail this process and compute the growing time scales and oscillation frequencies as a function of the mirror's location. It is found that in order for the system black hole plus mirror to become unstable there is a minimum distance at which the mirror must be located. We also give an explicit example showing that such a bomb can be built. In addition, our arguments enable us to justify why large Kerr-AdS black holes are stable and small Kerr-AdS black holes should be unstable.
317 citations
01 May 2004
TL;DR: The results obtained seem to indicate that Particle Swarm Data Mining Algorithms are competitive, not only with other evolutionary techniques, but also with industry standard algorithms such as the J48 algorithm, and can be successfully applied to more demanding problem domains.
Abstract: Particle Swarm Optimisers are inherently distributed algorithms where the solution for a problem emerges from the interactions between many simple individual agents called particles. This article proposes the use of the Particle Swarm Optimiser as a new tool for Data Mining. In the first phase of our research, three different Particle Swarm Data Mining Algorithms were implemented and tested against a Genetic Algorithm and a Tree Induction Algorithm (J48). From the obtained results, Particle Swarm Optimisers proved to be a suitable candidate for classification tasks. The second phase was dedicated to improving one of the Particle Swarm optimiser variants in terms of attribute type support and temporal complexity. The data sources here used for experimental testing are commonly used and considered as a de facto standard for rule discovery algorithms reliability ranking. The results obtained in these domains seem to indicate that Particle Swarm Data Mining Algorithms are competitive, not only with other evolutionary techniques, but also with industry standard algorithms such as the J48 algorithm, and can be successfully applied to more demanding problem domains.
314 citations
TL;DR: Marked structure-activity relationships (SARs)--namely the number of hydroxyl ring substituents--were found to rule the biological effect of such systems.
312 citations
TL;DR: Portugal followed the trend of other Mediterranean countries like Spain (30%), Greece (31%), and Italy (36%) and showed the second‐highest mean values in overweight/obesity, which require a national intervention program to control childhood obesity.
Abstract: The aim of this study was to assess the prevalence of overweight and obesity in Portuguese children age 7-9 years and to analyze trends in body mass index (BMI) from 1970-2002. Data were collected from October 2002 to June 2003 in a random sample of Portuguese children. Height and weight were measured and BMI (Kg/m(2)) was calculated. The International Obesity TaskForce (IOTF) cutoffs to define overweight and obesity were used. In the total sample we found 20.3% of overweight children and 11.3% of obese children. These results indicate a prevalence of overweight/obesity of 31.5%. Girls presented higher percentages of overweight than boys except at age 7.5. Girls also showed a higher percentages of obesity than boys except at age 9. From 1970 to 1992 and 1992 to 2002, height, weight, and BMI increased at different velocities: weight increased faster than height, and, consequently, BMI increased more in the last period than in the first one, leading to an increase in obesity values. Compared to published data by IOTF on other European countries, who applied the same methods to define overweight and obesity, Portuguese children showed the second-highest mean values in overweight/obesity. Italy showed the highest values (36%). The present study shows a very high prevalence of overweight/obesity (31.5%) in Portuguese children compared to other European countries. Portugal followed the trend of other Mediterranean countries like Spain (30%), Greece (31%), and Italy (36%). These high values require a national intervention program to control childhood obesity.
306 citations
TL;DR: In this article, the electrochemical oxidation of the (+)-catechin was investigated, over a wide range of conditions, using cyclic, differential and square wave voltammetry.
TL;DR: In this article, an experimental study was performed to evaluate the bond strength between two concrete layers, for different techniques for increasing the roughness of the substrate surface, including wire-brushing, sand-blasting, chipping with a light jackhammer; or were left as-cast against steel formwork.
TL;DR: When exposed to Aβ, events associated with programmed cell death are activated in AD NT2 cybrids to a greater extent than they are in control cybrids or the native NT2 cell line, suggesting a role for mtDNA‐derived mitochondrial dysfunction in AD degeneration.
Abstract: Alzheimer’s disease (AD) brain reveals high rates of oxygen consumption and oxidative stress, altered antioxidant defences, increased oxidized polyunsaturated fatty acids, and elevated transition metal ions. Mitochondrial dysfunction in AD is perhaps relevant to these observations, as such may contribute to neurodegenerative cell death through the formation of reactive oxygen species (ROS) and the release of molecules that initiate programmed cell death pathways. In this study, we analyzed the effects of beta-amyloid peptide (Ab )o n human teratocarcinoma (NT2) cells expressing endogenous mitochondrial DNA (mtDNA), mtDNA from AD subjects (AD cybrids), and mtDNA from age-matched control subjects (control cybrids). In addition to finding reduced cytochrome oxidase activity, elevated ROS, and reduced ATP levels in the AD cybrids, when these cell lines were exposed to Ab 1–40 we observed excessive mitochondrial membrane potential depolarization, increased cytoplasmic cytochrome c, and elevated caspase-3 activity. When exposed to Ab, events associated with programmed cell death are activated in AD NT2 cybrids to a greater extent than they are in control cybrids
TL;DR: The voltammetric oxidation of all deoxyribonucleic acid (DNA) monophosphate nucleotides is investigated for the first time over a wide pH range by differential pulse voltammetry with a glassy carbon electrode.
TL;DR: It is concluded that COX catalytic activity is indeed diminished in AD platelet mitochondria, does not result from altered membrane fluidity, and is associated with ROS overproduction and ATP under-production.
TL;DR: New questions concerning novel structure-function relationships among plant aspartic proteinases are now starting to be addressed, and their involvement in protein processing or degradation under different conditions and in different stages of plant development suggests some functional specialization.
Abstract: Aspartic proteinases of the A1 family are widely distributed among plant species and have been purified from a variety of tissues. They are most active at acidic pH, are specifically inhibited by pepstatin A and contain two aspartic residues indispensible for catalytic activity. The three-dimensional structure of two plant aspartic proteinases has been determined, sharing significant structural similarity with other known structures of mammalian aspartic proteinases. With a few exceptions, the majority of plant aspartic proteinases identified so far are synthesized with a prepro-domain and subsequently converted to mature two-chain enzymes. A characteristic feature of the majority of plant aspartic proteinase precursors is the presence of an extra protein domain of about 100 amino acids known as the plant-specific insert, which is highly similar both in sequence and structure to saposin-like proteins. This insert is usually removed during processing and is absent from the mature form of the enzyme. Its functions are still unclear but a role in the vacuolar targeting of the precursors has been proposed. The biological role of plant aspartic proteinases is also not completely established. Nevertheless, their involvement in protein processing or degradation under different conditions and in different stages of plant development suggests some functional specialization. Based on the recent findings on the diversity of A1 family members in Arabidopsis thaliana ,n ew questions concerning novel structure–function relationships among plant aspartic proteinases are now starting to be
TL;DR: The inflammatory response represents a fundamental ability of the organism to protect itself from infectious agents and from injury and is a keystone of the immune system.
Abstract: Summary
Background Psoriasis is a chronic and recurrent inflammatory skin disease. The inflammatory response represents a fundamental ability of the organism to protect itself from infectious agents and from injury.
Objectives To evaluate the inflammatory response in mild and in severe psoriasis, to evaluate the endogenous systems counterbalancing the deleterious effects of the inflammation products, and to establish values of prognostic significance.
Methods The study was performed in a control group (n = 40) and in 60 patients with psoriasis vulgaris, half presenting with mild psoriasis, and the other half with severe psoriasis. We evaluated total and differential leucocyte count; elastase, lactoferrin and lipid peroxidation as markers of neutrophil activation; total plasma antioxidant capacity (TAS), transferrin, ceruloplasmin, α1-antitrypsin and α2-macroglobulin as markers of the endogenous antioxidant and antiprotease systems; and fibrinogen, erythrocyte sedimentation rate, C-reactive protein (CRP), haptoglobin, C3 and C4 complement proteins as markers of inflammation.
Results Our data suggested that psoriasis is an inflammatory condition in which neutrophils seem to play a crucial role by contributing to the development of oxidative and proteolytic stress. The worsening of the disease seemed to be linked to the enhancement of the inflammatory response and of the imbalance between neutrophil activation products and their inhibitors.
Conclusions We propose values for elastase, CRP, elastase/α2-macroglobulin, elastase/α1-antitrypsin, thiobarbituric acid/TAS and elastase/neutrophil ratios with prognostic significance for the worsening of psoriasis.
TL;DR: In this paper, a generalized relativistic harmonic oscillator for spin 1∕2 particles is studied, and analytical solutions for bound states of the corresponding Dirac equations are found.
Abstract: A generalized relativistic harmonic oscillator for spin 1∕2 particles is studied. The Dirac Hamiltonian contains a scalar $S$ and a vector $V$ quadratic potentials in the radial coordinate, as well as a tensor potential $U$ linear in $r$. Setting either or both combinations $\ensuremath{\Sigma}=S+V$ and $\ensuremath{\Delta}=V\ensuremath{-}S$ to zero, analytical solutions for bound states of the corresponding Dirac equations are found. The eigenenergies and wave functions are presented and particular cases are discussed, devoting a special attention to the nonrelativistic limit and the case $\ensuremath{\Sigma}=0$, for which pseudospin symmetry is exact. We also show that the case $U=\ensuremath{\Delta}=0$ is the most natural generalization of the nonrelativistic harmonic oscillator. The radial node structure of the Dirac spinor is studied for several combinations of harmonic-oscillator potentials, and that study allows us to explain why nuclear intruder levels cannot be described in the framework of the relativistic harmonic oscillator in the pseudospin limit.
TL;DR: In a cohort of patients in whom airway pressures and tidal volume are limited, barotrauma is more likely in patients ventilated due to underlying lung disease (acute or chronic) and was also associated with a significant increased in the ICU length of stay and mortality.
Abstract: Objective
To determine the incidence, risk factors, and outcome of barotrauma in a cohort of mechanically ventilated patients where limited tidal volumes and airway pressures were used.
TL;DR: It is the opinion of the EULAR executive committee members that “guidelines” might appear too constraining and that, on the other hand, “points to consider’ might be considered as too open.
Abstract: It is the objective of the EULAR executive committee to promote actions and/or projects aimed at improving the knowledge and/or the recognition of musculoskeletal disorders.
The chief aim is to contribute to the improvement of outcome of patients with rheumatic disorders. Apart from the projects devoted to education and research, projects aimed at facilitating the conduct of clinical studies or at improving the management of musculoskeletal disorders are welcome. Such studies can be categorised in four sections:
It is the objective of the EULAR executive committee to maintain and to homogenise a high level of intrinsic quality and comparability of such studies.
To achieve such an objective it appeared that the definition and publication of standardised procedures for the elaboration, evaluation, dissemination, and implementation of recommendations might be a relevant and useful starting point.
Obviously these standardised operating procedures should not be a barrier to acceptance of a project if not all points are satisfied but might be important to consider before starting a project.
These recommendations are not mandatory in themselves but can be used flexibly.
At each step of such projects (application, elaboration, dissemination, etc), the individual items summarised in table 1 should be discussed. The reader is invited to visit the EULAR website (http://www.eular.org) to check the most recently updated version of these procedures.
### A Which wording?
The three proposals are “points to consider”, “recommendations”, “guidelines”.
It is the opinion of the EULAR executive committee members that, on the one hand, “guidelines” might appear too constraining and that, on the other hand, “points to consider” might be considered as too open. Recommendations can …
TL;DR: In the long term, sustained eutrophication of this estuary is expected to lead to complete replacement of seagrass habitat by unvegetated coarser sediments, occasionally covered by green macroalgal blooms and dominated by opportunistic invertebrate taxa.
TL;DR: It is concluded that the cardioprotective effects of carvedilol against DOX-induced mitochondrial cardiotoxicity are due to its inherent antioxidant activity and not to its beta-adrenergic receptor antagonism.
TL;DR: The Retinal Leakage Analyzer, maps BRB alterations and has opened new perspectives for multimodal macula mapping and improved evaluation of newly available drugs that show promise for stabilizing the BRB.
TL;DR: In this paper, the primal-dual interior-point filter is used to solve the problem of global convergence to first-order critical points in nonlinear nonlinear programs, without the use of merit functions and penalty parameters.
Abstract: In this paper, the filter technique of Fletcher and Leyffer (1997) is used to globalize the primal-dual interior-point algorithm for nonlinear programming, avoiding the use of merit functions and the updating of penalty parameters.The new algorithm decomposes the primal-dual step obtained from the perturbed first-order necessary conditions into a normal and a tangential step, whose sizes are controlled by a trust-region type parameter. Each entry in the filter is a pair of coordinates: one resulting from feasibility and centrality, and associated with the normal step; the other resulting from optimality (complementarity and duality), and related with the tangential step.Global convergence to first-order critical points is proved for the new primal-dual interior-point filter algorithm.
TL;DR: In this paper, the authors present a conceptual framework outlining the evolution of manufacturing performance measures and measurement in an organizational context, and identify and discuss several issues relevant to both practice and theory of the manufacturing performance measurement.
Abstract: Competitive pressures in the global manufacturing environment are forcing manufacturing organizations to re‐engineer in order to become more competitive in the marketplace. Toward that end, management of these organizations is paying closer attention to the changing nature of manufacturing performance, and the systems, processes and measures used in its evaluation. Examines the literature concerned with issues related to the different facets of manufacturing organizational performance. Reviews and classifies articles published in relevant journals between 1988 and 2000. Based on this extensive literature review, identifies and discusses several issues relevant to both practice and theory of manufacturing performance measurement. Concludes by presenting a conceptual framework outlining the evolution of manufacturing performance measures and measurement in an organizational context.
TL;DR: In patients with cholestatic liver disease, the extent of hepatocyte damage caused by intracellular accumulation of bile acids appears to be delayed by ingesting a hydrophilic bile acid, but its effects on disease progression are not completely clarified.
TL;DR: It is concluded that at least some of the linkage peaks identified may have been largely undetected in previous whole-genome scans for bipolar disorder because of insufficient coverage or information content, particularly on chromosomes 6q22 and 11p11.
Abstract: We performed a linkage analysis on 25 extended multiplex Portuguese families segregating for bipolar disorder, by use of a high-density single-nucleotide–polymorphism (SNP) genotyping assay, the GeneChip Human Mapping 10K Array (HMA10K). Of these families, 12 were used for a direct comparison of the HMA10K with the traditional 10-cM microsatellite marker set and the more dense 4-cM marker set. This comparative analysis indicated the presence of significant linkage peaks in the SNP assay in chromosomal regions characterized by poor coverage and low information content on the microsatellite assays. The HMA10K provided consistently high information and enhanced coverage throughout these regions. Across the entire genome, the HMA10K had an average information content of 0.842 with 0.21-Mb intermarker spacing. In the 12-family set, the HMA10K-based analysis detected two chromosomal regions with genomewide significant linkage on chromosomes 6q22 and 11p11; both regions had failed to meet this strict threshold with the microsatellite assays. The full 25-family collection further strengthened the findings on chromosome 6q22, achieving genomewide significance with a maximum nonparametric linkage (NPL) score of 4.20 and a maximum LOD score of 3.56 at position 125.8 Mb. In addition to this highly significant finding, several other regions of suggestive linkage have also been identified in the 25-family data set, including two regions on chromosome 2 (57 Mb, NPL = 2.98; 145 Mb, NPL = 3.09), as well as regions on chromosomes 4 (91 Mb, NPL = 2.97), 16 (20 Mb, NPL = 2.89), and 20 (60 Mb, NPL = 2.99). We conclude that at least some of the linkage peaks we have identified may have been largely undetected in previous whole-genome scans for bipolar disorder because of insufficient coverage or information content, particularly on chromosomes 6q22 and 11p11.
TL;DR: Overall results showed that avoidance tests with collembolans and earthworms have the potential to be used as screening tools in ecological risk assessment schemes for contaminated land, to trigger other tests in case of concern.
Abstract: Avoidance tests with earthworms and collembolans were conducted to demonstrate their feasibility as early screening tools for assessing the toxic potential of metal-polluted soils. Four different soils, with different degrees of metal contamination, were obtained from an abandoned mining area. All possible paired combinations were assessed for an avoidance response by the organisms. Data revealed that both species were able to avoid the most contaminated soils at the center of the ore extraction and treatment areas compared to those collected further away from the mine. However, earthworms and springtails differed in sensitivity to metals, especially when testing the two most polluted soils that had different contamination profiles. Earthworms exhibited a more consistent, less variable response than springtails. Overall results showed that avoidance tests with collembolans and earthworms have the potential to be used as screening tools in ecological risk assessment schemes for contaminated land, to trigger other tests in case of concern. However, further method development is needed to reduce variability in the data, particularly in the Collembola assays, and to gain knowledge about the possible effects of soil properties on the outcome of the tests.
TL;DR: The results suggest that the population of S. Domingos mine area and neighbour localities may be exposed to some of the elements analysed namely Mn and Zn.
TL;DR: In this paper, a multiple objective mixed integer linear programming model for power generation expansion planning is presented, which allows the consideration of modular expansion capacity values of supply-side options, and demand-side management is also considered an option in the planning process, assuming there is a sufficiently large portion of the market under franchise conditions.